Tissue (e.g., neural or muscular tissue) stimulation is a well accepted clinical method for reducing pain in certain populations of patients. Implantable stimulation devices have been developed to provide therapy for a variety of treatments. For example, implantable stimulation devices can be used to stimulate nerves, such as the spinal cord, muscles, or other tissue. An implantable stimulation device typically includes an implantable control module with a pulse generator (although in some instances the control module or pulse generator may not be implanted), a lead, and an array of stimulator electrodes. The stimulator electrodes are implanted in contact with or near the nerves, muscles, or other tissue to be stimulated. The pulse generator in the control module generates electrical pulses that are delivered by the electrodes to body tissue. As an example, electrical pulses can be provided to the dorsal column fibers, or other neural tissue, within the spinal cord to provide spinal cord stimulation.
The stimulator electrodes are coupled to the control module by the lead and the control module is implanted elsewhere in the body, for example, in a subcutaneous pocket. The lead is often anchored at one or more places in the body to prevent or reduce movement of the lead or stimulator electrodes within the body which could damage tissue, move the stimulator electrodes out of the desired position, or interrupt the connection between the stimulator electrodes and the control module.
Ideally, lead anchors should be constructed of strong, biocompatible materials and should be small, light-weight and easy to use. Many conventional lead anchors are difficult to use without being overly invasive. Most use sutures to secure the lead anchor to the surrounding tissue in order to keep it in place. One problem suturing an anchor in place is that the sutures should be tight enough to keep the lead anchor from being dislodged, but not so tight as to damage the lead itself, which could result in lead failure. This requires a level of skill on the part of the clinician, which necessitates practice before the clinician is able to consistently install the lead anchor properly. In addition, it often requires substantial surgical time to properly secure the lead anchor.
Conventional lead anchors may not sufficiently grip the lead to keep the lead in place. As a consequence, the lead may migrate away from the intended stimulation site.